1. Field of the Invention
This invention relates to an abrasive cleaning apparatus and more particularly to an apparatus utilizing the reaction force of a cleaning nozzle to move the nozzle across a work surface.
2. Description of the Prior Art
The sand blasting of a surface prior to painting or simply cleaning as is in the case of stone or brick walls is a common practice. Generally this is accomplished by an operator positioned on a scaffold or other suitable support manually manipulating at least one discharge nozzle. Obviously the presence of the operator in this work zone makes this an extremely dirty and hazardous occupation. Moreover, the limited volume of sand blasted against the surface by a single nozzle is a very inefficient operation.
As a result, abrasive blasting apparati, particularly used for large surface areas, may employ multiple rather than a single blast nozzle. The obvious advantage of this being a greatly increased blast pattern. Due to the increased weight and speed of operation, multiple nozzles are often carried on a movable carriage or platform on which the operator rides. The platform is movable laterally and vertically along the area to be cleaned and results in significant labor saving devices.
Unfortunately, a number of difficulties have been experienced which hindered general acceptance and wide use for the multi-nozzle head. For example, many multi-nozzle head systems mix the sand and air in a common reservoir to discharge from the nozzles which communicate directly with the reservoir. In another configuration, the operator may be provided with two separate nozzles each having its own supply lines. In either of these arrangements, individual control of the nozzles is lacking to the extent that the blast stream in one nozzle cannot be cut off independently of the other. Such independent manipulations of the blast from the different nozzles is desirable in situations involving spots or areas which present a difficult cleaning problem. The blast from one nozzle must work on the difficult area for a prolonged period during which time other blasts will be damaging clean metal in the surrounding area.
Another difficulty with previous multi-blast carriage arrangements is that the units are very cumbersome and complex so as to be suitable only for special cleaning operations. Also many such multiple nozzle machines have lacked adequate flexibility of movement and could not be easily manipulated.
More unique problems exist with respect to the development of such apparatus for cleaning the undersides of ships in dry dock where there is very little clearance between the hull and the floor of the dry dock. Bulky machines cannot extend between the hull and the dry dock.
In my prior U.S. Pat. No. 4,027,433, I disclosed a sand blasting apparatus incorporating a plurality of nozzles mounted on an adjustable nozzle support. This patent has solved many of the needs as set forth in the prior art. In my subsequent U.S. Pat. No. 4,126,970, I utilized the multiple nozzles of my first patent and harnessed the reaction force produced by the plurality of nozzles to sweep the nozzles across a work surface. This device enabled an operator to control the movement of the nozzles about a first axis in accordance with the rotation of the nozzles about a second axis established at an angle relative to the first axis.
In the present invention, I have further improved my previous inventions to provide an apparatus which requires minimal physical manipulation by an operator. Accordingly, it is a primary object of this invention to provide an improved apparatus for cleaning a work surface by blasting the surface with an abrasive which overcomes the problems of the prior art and which improves upon my two prior inventions.
Another object of this invention is to provide an apparatus for cleaning a work surface by blasting the surface with an abrasive wherein an actuator rotates the abrasive cleaning nozzle about a second axis to control the reaction force of the nozzle, thereby enabling automatic alternate sweeping across the work surface about a first axis.
Another object of this invention is to provide an apparatus for cleaning a work surface by blasting surface with an abrasive including base drive means for linearly moving the base relative to the work surface upon alternate sweeps of the nozzle thereby coordinating the alternate sweeping and linear movement of the nozzle across the work surface.
Another object of this invention is to provide an apparatus for cleaning a work surface by blasting the surface with an abrasive wherein the apparatus comprises a cart mounted on plural wheels which wheels are adjustable for positioning between beams of a vessel or building structure.
Another object of this invention is to provide an apparatus for cleaning a work surface by blasting the surface with an abrasive including an improved adjustable nozzle support for supporting a plurality of nozzles in a substantially parallel array wherein the stacking of the plurality of nozzles may be varied within the parallel array to vary the blast pattern of the apparatus.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.